The objective of this study is to determine the efficacy of a clinical score in determining left-to-right ductal shunt flow as compared to state of the art echocardiographic techniques. A clinical and echocardiographic score will be obtained on all admissions to the NBICU at three different times which optimizes the liklihood of changing ductal flow dynamics, and thus, the subjects will serve as their own controls. Each component of the clinical score will also be analyzed individually as to predictability of significant ductal shunting.